Two port vector network analyzer using de-embed probes

Abstract

A test and measurement system including a device under test, two de-embed probes connected to the device under test, and a test and measurement instrument connected to the two de-embed probes. The test and measurement instrument includes a processor configured to determine the S-parameter set of the device under test based on measurements from the device under test taken by the two de-embed probes.

1 . A method for determining an S-parameter set of a device under test using a test and measurement instrument, comprising:
 measuring an impedance of a signal generator with a first de-embed probe;   measuring an input voltage to the device under test with the first de-embed probe connected to the input of the device under test;   measuring an output voltage from the device under test with a second de-embed probe connected to the output of the device under test;   measuring three loads of the device under test with the first de-embed probe connected to the input of the device under test and the second de-embed probe connected to the output of the device under test; and   calculating the S-parameter set of the device under test based on the impedance of the signal generator, the input voltage to and the output voltage from the device under test, and the measured three loads of the device under test.   
     
     
         2 . The method of  claim 1 , wherein the measuring of the impedance of the signal generator with the first de-embed probe is performed with the device under test not connected to the first de-embed probe or the second de-embed probe. 
     
     
         3 . The method of  claim 2 , wherein the measuring of the input voltage of the device under with the first de-embed probe is performed with the device under test not connected to the second de-embed probe. 
     
     
         4 . The method of  claim 3 , wherein the measuring of the output voltage of the device under test with the second de-embed probe is performed with the device under test and the signal generator not connected to the first de-embed probe. 
     
     
         5 . The method of  claim 2 , wherein the measuring of the input voltage of the device under test and the measuring of the output voltage of the device under test are performed when the first de-embed probe is connected to the input of the device under test and when the second de-embed probe is simultaneously connected to the output of the device under test. 
     
     
         6 . The method of  claim 1 , further comprising:
 measuring a second impedance of the device under test and the signal generator with the second de-embed probe; and   measuring a second output voltage of the device under test with the second de-embed probe connected to the output of the device under test and the signal generator,   wherein the calculating step further includes calculating the S-parameter set based on the second impedance and the second output voltage from the device under test.   
     
     
         7 . The method of  claim 1 , wherein the test and measurement instrument is a digital storage oscilloscope or a spectrum analyzer. 
     
     
         8 . The method of  claim 1 , wherein the signal generator is a step generator. 
     
     
         9 . A method for determining an S-parameter set of a device under test with more than two ports using a test and measurement instrument, comprising:
 performing the method of  claim 1  on each two port combination of the more than two ports of the device under test with the remaining ports terminated with a reference impedance; and   calculating the S-parameter set of the device under test based on the parameters determined for all the two port combinations.   
     
     
         10 . A test and measurement system for measuring an S-parameters set of a device under test, comprising:
 a signal generator;   a first de-embed probe configured to measure an impedance of the signal generator and an input voltage of the device under test;   a second de-embed probe configured to measure an output voltage of the device under test and an impedance of the device under test,   wherein the first de-embed probe and the second de-embed probe are configured to measure at least three loads when both the first de-embed probe and the second de-embed probe are connected to the device under test; and   a processor configured to calculate the S-parameter set of the device under test based on the impedance of the signal generator, the input voltage and the output voltage of the device under test, and the measured three loads of the device under test.   
     
     
         11 . The system of  claim 10 , further including a test fixture including a first port and a second port, wherein the first de-embed probe connects to the signal generator and the device under test through the first port, and the second de-embed probe connects to the device under test through the second port. 
     
     
         12 . The system of  claim 10 , wherein the signal generator is located within a test and measurement instrument. 
     
     
         13 . The system of  claim 10 , wherein the signal generator is external to a test and measurement instrument. 
     
     
         14 . The system of  claim 10 , wherein the processor is located within a test and measurement instrument. 
     
     
         15 . The system of  claim 10 , wherein the processor is external to a test and measurement instrument. 
     
     
         16 . The system of  claim 12 , wherein the test and measurement instrument is a digital storage oscilloscope or spectrum analyzer. 
     
     
         17 . The system of  claim 10 , wherein the signal generator is a step generator. 
     
     
         18 . A test and measurement system, comprising:
 two de-embed probes configured to connect to a device under test and configured to take measurements of the device under test; and   a processor configured to receive the measurements taken by the two de-embed probes and to determine the S-parameter set of the device under test based on the measurements of the device under test.